1. Field
This invention relates generally to endotracheal procedures and is specifically directed to the delivery of surfactant to lung tissues in connection with such procedures. It provides a system which permits the delivery of surfactant through an artificial airway of an endotracheal ventilation/aspiration system without interrupting ventilation.
2. State of the Art
Many gas delivery systems, particularly in a hospital or laboratory environment, utilize manifold devices for directing fluid flow. There is a variety of circumstances in which it is necessary or desirable to provide multiple, yet isolated, other pathways through the interior of such a manifold. The manifold is often associated with other components as a system. When the individual components of such a system are subjected to mechanical forces tending to rotate one component with respect to another, it is often desirable to provide that travel path through a joint structure which permits rotating or swiveling movement.
As an example, closed systems for endotracheal suctioning and ventilating typically include a manifold structured to enable the introduction of ventilating gases and intermittent exhalation of patient breath simultaneously with insertion and operation of a tracheal suctioning catheter. The manifold structure typically includes multiple ports, usually the open ends of respective conduits extending from a common chamber. One such port is interfaced to a patient through a patient connection device, which in turn provides access to an artificial airway positioned within the patient by a predicate intubation procedure. The suction catheter is often included within an assembly, which is connectable to a second port of the manifold. The catheter assembly conventionally includes a collapsible plastic envelope positioned to entirely surround the catheter. A practitioner manually externally collapses the envelope onto the external surface of the catheter and advances the catheter through the manifold into an access tube connected to a patient, retracting the catheter in a similar fashion following the aspiration procedure.
The manifold thus provides a first pathway for ventilation gases and a second pathway for the catheter. The catheter provides isolation from the ventilating gases for fluids withdrawn from the patient through the manifold. When the catheter is withdrawn, it is often desired to continue regulated ventilation through the manifold. In some cases, it is desirable for the catheter assembly to be disconnected from the manifold without disturbing the ventilation of the patient. Certain manifold assemblies are thus structured to provide for a gastight sealing of the pathway formerly occupied by the catheter upon its removal.
Material prior art structures and methods are described, among other places, in U.S. Pat. No. 5,333,607 to Kee, et al.; U.S. Pat. No. 5,354,267 to Niermann, et al.; U.S. Pat. Nos. 5,357,946 and 5,445,141 to Kee, et al.; U.S. Pat. Nos. 5,140,983 and 5,487,381 to Jinotti; U.S. Pat. No. 5,882,348 to Winterton et al.; U.S. Pat. Nos. 5,735,271 and 5,730,123 to Lorenzen et al. and U.S. Pat. No. 5,642,726 to Owens et al. These patents each disclose ventilator manifold devices (some of which are assemblies of components) and systems with which those devices are utilized. The '267 patent, for example, discloses an assembly including a manifold and an associated multiposition stop cock valve. The valve is provided with a “Tee”-shaped internal stem channel pattern so that the stem may be positioned selectively to wash the internal lumen of a catheter to irrigate the patient or to accommodate travel of the catheter through the stem to suction the patient. The valve may be plugged directly into an access port of the manifold. Patient ventilation is conducted without respect to the valve through other ports of the manifold. The valve itself constitutes an integral component of a catheter assembly and must be removed from the remainder of the manifold with the remainder of that assembly. The '348 patent discloses a valved manifold embodying a multiposition stop cock valve. This manifold may be integral with a catheter assembly, but is alternatively structured to be detachable from the catheter assembly. The ventilation port is transverse the patient interface port and is, thus, characterized by more dead airspace than is generally regarded as acceptable for neonatal applications.
The disclosure of commonly assigned, copending U.S. patent application Ser. No. 09/723,011, filed Nov. 27, 2000, entitled “NEONATAL VALVED MANIFOLD,” is hereby incorporated herein by reference. Ser. No. 723,011 discloses a manifold assembly incorporating a valve constructed and arranged to minimize dead airspace within the manifold, while remaining capable of passing a catheter. The disclosed valve provides a sealed gas flow path through the manifold in both its open and closed conditions with respect to catheter travel. The manifold may be constructed as either integral with or detachable from any associated catheter assembly. It includes a ventilation port that is substantially axially aligned with the patient interface port and is constructed to minimize fluid flow turbulence of ventilating gases, among other features particularly advantageous to neonatal applications.
Neonatal endotracheal procedures present a number of special problems. Of particular interest to this invention is the low level of surfactant naturally present in neonatal lung tissues. Endotracheal procedures that are routinely performed on juveniles or adults are impracticable to apply to neonatal tissues without taking steps to compensate for these low surfactant levels. It has become an accepted procedure to introduce surfactant (usually obtained from bovine or equine lung tissue) to the proximity of neonatal lung tissue prior to commencing suctioning procedures. Surfactant has typically been introduced by injection from a syringe through the artificial airway that is inevitably present following a conventional intubation procedure. Because of the tendency for injected surfactant to become entrapped within the artificial airway, however, more recent techniques involve the injection of surfactant through a catheter inserted down the artificial airway to beyond its termination. Discharge of the surfactant beyond the artificial airway ensures actual delivery of the surfactant to lung tissue and avoids the potential for blow back of surfactant during subsequent ventilation. A feeding tube (typically a 5F size) has conventionally been used for this purpose, with the ventilation circuit absent from the artificial airway. More recently, special catheters, such as the multiple access catheter (MAC) marketed by the Ballard Medical Products subsidiary of Kimberly-Clark Health Care of Roswell, Ga., under the marks “KIMBERLY CLARK BALLARD” and “TRACH CARE” have been offered as a means for maintaining PEEP and Oxygen levels during surfactant delivery. Use of these delivery systems inevitably requires breaking the ventilation circuit, however, to exchange the surfactant and suction catheters required for the complete endotracheal procedure. A need thus remains for an improved surfactant delivery method and apparatus which avoids the interruption of ventilation.